Right, not good = unethical :).
Maybe…but not necessarily 
~TehYoyo
Off Topic:
I don’t think it is so easy to draw the line & say all copying is wrong or even copying of copyrighted material. I think a good example would be this series http://www.everythingisaremix.info/watch-the-series/ . The fashion industry is a thriving copy-cat community (fashion is considered to utilitarian to be copyrighted). http://www.ted.com/talks/johanna_blakley_lessons_from_fashion_s_free_culture.html . Whilst strictly copy something thread for thread I’d consider wrong, or maybe even just dumb, getting ideas from someone else and using a small part of someone else work/idea in something of your own that could be considered original I would not consider unethical. And just for fun a brief history of copyright http://www.youtube.com/watch?v=tk862BbjWx4 . Sure copyright is a good thing but I think it’s power is abused.
I think it is. If you copy w/out consent, that’s bad (and that’s the end of the story, in my opinion).
Whilst strictly copy something thread for thread I’d consider wrong, or maybe even just dumb, getting ideas from someone else and using a small part of someone else work/idea in something of your own that could be considered original I would not consider unethical.
Now you’re talking about inspiration vs. copying, which has been talked about extensively (this is just one example). There’s always a fine line b/w the two, and it’s very subjective as to what’s what.
~TehYoyo